Spiny Haplopappus
Lacy Tansy Aster

Xanthisma spinulosum
(Machaeranthera pinnatifida)

Machaeranthera pinnatifida Watercolor © by Michael Plagens

Watercolor (© Mike Plagens) from live specimen observed at Camp Creek, Maricopa Co., Arizona, USA on 18 April 1992. A) Dainty Sulfur, Nathalis iole.

FLOWERS: Ray flowers yellow as are the disc flowers. The number and length of the yellow rays varies considerably as does the finer characteristics of the foliage. Many varieties have been named as a result.
Xanthisma spinulosum photo © by Michael Plagens
PERENNIAL: The above ground branches are mostly herbaceous, but the crown and root stock of older plants may become woody.

RANGE: A common plant above 800 m elevation throughout the Sonoran Desert with a lot of variation in the leaves, spininess, and size of flowers.

LEAVES: The leaves normally have prickly teeth along the margins.

ACHENE: The achene carries a pappus of tan, fine bristles.

The Dainty Sulfur (Nathalis iole), the smallest of the yellow butterflies, is a common associate of this plant because the caterpillars eat the leaves.

Asteraceae -- Sunflower Family

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More Information:

Sonoran Desert Field Guide
Sonoran Desert Places
Sonoran Desert Naturalist Home Page


Copyright Michael J. Plagens, page created 1 May 2004,
updated 21 March 2016